CHAPTER 2 MATTER AND CHANGE:

2.1 PROPERTIES OF MATTER Describe matter by looking! Extensive Properties – depends on the amount of matter in a sample examples- volume and mass b. Intensive Properties – depends on the type of matter in a sample example – bowling ball

Identifying Substances: Substance: matter that has a uniform and definite composition Physical property: the quality of a sample that can be observed or measured without changing the substance’s composition. Hardness Color Malleability Conductivity Ductile

STATES OF MATTER Solid – definite shape definite volume – atoms vibrate in fixed position Liquid – indefinite shape definite volume – atoms are in close contact but not rigid Gas – takes shape and volume of container – atoms are active and far apart As energy in the substance increases the atoms motion increases! What is the difference between gas and vapor?

PHYSICAL CHANGES Properties of a material change but the composition remains the same. Freeze Melt Condense Break Split Grind Evaporate Sublimate How can physical changes be reversible or irreversible?

2.2 MIXTURES Mixture – a physical blend of two or more substances Heterogeneous – uneven mixture composition Homogeneous – even mixture composition What is a phase?

SEPERATING MIXTURES Filtration Distillation Magnetism

2.3 ELEMENTS AND COMPOUNDS Element – simplest form of matter and cannot be broken down into simpler substances. Compound – a substance that contains two or more elements chemically combined in a fixed proportion and it can be broken down into simpler substances by chemical means

Chemical Change: If a substance takes on new properties from the combination or separation of element in the substance Heat is a good catalyst – what is a catalyst? What might give you a clue a chemical change has occurred?

SYMBOLS AND FORMULAS Symbols – one or two letters used to identify an element Formulas – a shorthand way to identify a compound or molecule

CONSERVATION OF MASS The mass of the product always equals the mass of the reactants so in any physical or chemical change mass is conserved.